The delightfully disheveled Mr. Walentas, “whose daily uniform usually consists of a hoodie and jeans,” speaks on topics ranging from his domains in Dumbo and Hells Kitchen to art and air hockey. The most striking passage, though, is his staunch defense of development as a social good for New York.

“Unlike someone on Wall Street, who can make a lot of money in New York and then move on,” he said, “we are in it for the long term.” He was standing in the construction zone for the second phase of Mercedes House, so named because the ground-floor commercial space is leased to a Mercedes-Benz dealership. “This building will be here for a hundred years. It’s not like we can load it onto a 747 and move it. And for it to be successful, the neighborhood needs to be successful.”

Still, there is no getting around the fact that new construction in New York’s prime neighborhoods is geared toward the wealthy.

When David Walentas bought two million square feet of space in Dumbo in 1981, he paid $12 million. Today, a single penthouse apartment in the ClockTower building in that neighborhood is listed for $23 million.

So it comes as little surprise that developers are often accused of creating playgrounds for the privileged. The younger Mr. Walentas said he understood the concern. But, he argued, it is the conditions surrounding new construction that often drive up costs for everyone.

“The reason real estate is so expensive is because it is so difficult to build,” he said.

To Mr. Walentas credit, he is at least reserved in his wealth, and not just because of what he wears. He converted his Soho loft himself from an old theater space; he gives back to “projects involving education, cultural institutions in Brooklyn, and art in public spaces;” and his home would be as messy as his notorious office if it were not for his lovely wife. His most absurd purchase? A vintage bubble hockey game he plays with his high school friends. It certainly beats a private jet.